Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
The semiconductor industry continues to improve the integration density of various electronic components (e.g., transistors, diodes, resistors, capacitors, etc.) by continual reductions in minimum feature size, which allow more components to be integrated into a given area. These smaller electronic components also require smaller packages that utilize less area than packages of the past. Electronic components may be built vertically from the substrate, permitting greater numbers of components to be located in a given area.
Electronic components may be fabricated using layering techniques. Passivation layers, metallization layers, dielectric layers, masks and the like may all be deposited over a substrate. In some instances, layers may be manipulated or modified after deposition. Some layers, such as masks, passivation layers, dielectric layers and metallization layers may be polished, through, for example, a chemical mechanical polish or the like. Planar surfaces to these layers results in fewer errors in subsequent layers.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.